This invention relates to a method of cleaning the interior of a polymerization reactor. More particularly, it relates to a method of removing scales or other materials deposited on the inside of a polymerization reactor used in emulsion polymerization or suspension polymerization.
Plant cleaning techniques include mechanical cleaning and chemical cleaning. The mechanical cleaning includes a high-pressure jet cleaning, a blast cleaning, and a pig cleaning. The chemical cleaning includes an alkali cleaning, an acid cleaning, and an emulsion cleaning. The alkali cleaning is generally used for removing oils and fats by use of caustic soda, sodium carbonate, etc. The acid cleaning is usually used for cleaning and removing inorganic scales, etc., with hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. The emulsion cleaning is adapted to cleaning and removing oils and fats with a surfactant, etc.
To remove the scales deposited on the interior of the polymerization reactor such as the inside surface of the reactor, an agitator, and baffle-plates, mechanical cleaning is generally used, particularly, high-pressure jet cleaning. It is usually difficult, however, for the high-pressure jet cleaning to remove scales completely. In addition, to apply a scale deposition preventing agent having a chelate forming function on the inside surface of polymerization reactor, it is necessary to completely clean the inside surface of the reactor in advance. The high-pressure jet cleaning cannot be used for such a purpose since it does not completely remove scales.